Fish are dying in Caldwell pond

CALDWELL -- Hundreds of small sunfish have mysteriously died in a small park pond in the last week.

“I’ve never seen anything like it before,” said Kashmir Singh, who has maintained the Grover Cleveland Park for eight years.

Singh, who was walking around the pond with a pool skimmer Friday, said many of the fish developed a fuzzy, white growth on their heads.

“It almost looks like a barnacle on the fish, and then soon after it appears, the fish dies,” said Bruce Davita, chief project coordinator for the Essex County Parks Department.

More than 300 sunfish in the pond have died this way, Davita said. Before the mold-like substance grows, the fish turns a dark brown or black color.

The pond, located at Brookside Avenue and Runnymede Road, is the site where the county plans to kick off a fishing derby May 1. Davita said a state Fish and Wildlife biologist told him there’s no health concern.

“He just suggested that people don’t eat the fish,” Davita said. “I think if someone caught one of those, and it has the white growth, I don’t think people would eat it anyway.”

Lawrence Hajna, a spokesman for the New Jersey Department of Environmental Protection, said a biological pathogen appears to be killing the fish, which is common this time of year during spawning season. The fish are “stressed out” from spawning, making them more susceptible to a virus or bacteria in the water.

“We’re not seeing evidence that it was pollution,” Hajna said.

In Ridgewood, some 15 miles away, about 50 dead sunfish were found at the Wild Duck Pond in the course of two days this past week, Hajna said.

Davita said the state fish and wildlife division told him it appears the same naturally occurring bacteria is affecting fish in both ponds and possibly a third one in south Jersey. It was triggered when the weather warmed up quickly after the cold winter. The infection is killing only young, 2- to 3-inch-long sunfish and bass, although no dead bass were found in the Caldwell pond, Davita said.

The results of samples taken from the ponds is expected next week, Davita said.

A similar incident happened at Branch Brook Park in Newark two years ago, but the cause turned out to be a naturally occurring nitrogen build-up at the bottom of the lake, he said. Due to a change in weather, the nitrogen was released all at once and displaced the oxygen in the water, killing the fish. Fountain-like aerators placed in the water solved the problem.

For the Caldwell pond, Davita said officials plan to improve the water flow from a creek that runs into the pond by reconstructing an aging, decaying weir, an underwater dam, to force more water into the pond.

Although there doesn’t appear to be a danger to people’s health, Singh, the caretaker, said he’s spent every day since late last week pulling out dead fish. That may assuage the concern of catch-and-release fishermen like Ryan Rosselot.

“You’ve got a lot of kids who are fishing, catching little sunnies and touching them,” Rosselot said Tuesday, when he came to the Caldwell park to cast lines into the pond.